Cardiac MedicationsMildred Yarborough

Cardiac Medications

Part 2

Overview

Drugs used to treat arrhythmias Antiarrhythmic & Cardiac glycosides

Beta blockers & calcium channel blockers Drugs given intravenously to affect the

cardiovascular system Inotropes Adrenergic agonists

Antiarrhythmics

Class I Sodium Channel

Blockers

Class II Beta Blockers

Class III K+ Blockers,pro-

long repolorization

Class IV Calcium Channel

Blocker

Other

Lidocaine

Propafenone

Sotalol

Amiodarone

Diltiazem

Adenosine

Class I: Lidocaine

Shortens repolarization, raises VF threshold Administered IV life-threatening arrhythmias: VT, VF

short-term management Side effects: drowsiness, parasthesias, other CNS

effects Toxicity: seizures, respiratory depression, coma Contraindications: heart block

Class II: Sotalol

Beta blocker: decreases excitability of heart due to sympathetic stimulation

Uses: atrial and ventricular arrhythmias Oral administration Telemetry monitoring with initiating therapy Side effects: bradyarrhythmias, CHF, fatigue

Class III: Amiodarone

Prolongs action potential and refractory period, inhibits adrenergic stimulation Uses: supraventricular and ventricular

arrhythmias not responsive to other drugs Very effective! Potentially very toxic! Administered IV in ICU, emergencies;

usually oral administration Very long half life (up to several months)

Amiodarone

Side effects: anorexia, other GI, arrhythmias, others

Toxicities: pulmonary fibrosis, corneal micro-deposits, liver function abnormalities, hypothyroidism, others

Periodic monitoring for toxicities: pulmonary function tests, eye exam, LFTs

Class IV: Diltiazem

Calcium channel blocker slows AV node conduction and AV node

refractory period Uses: rate control in atrial fibrillation or

flutter IV used acutely Oral administration or another drug class for

chronic management

Diltiazem

Monitoring: telemetry, blood pressure Side effects: hypotension, arrhythmias,

CHF, edema Contraindication: 2nd or 3rd degree AV block, recent MI or pulmonary congestion

Others: Adenosine

Used for acute management of rapid SVT Must be given rapid IV (1-2 sec) : half life 10-20 seconds

IV push followed immediately by 20 CC NS Cardiac monitoring on Lifepac during

administration

Nursing Implications: Antiarrhythmics

Cardiac monitoring with initiation and dosage adjustment

Obtain ECG strip prior to administration Analyze for rate, rhythm, intervals

Be alert for changes over time Monitor for adverse & toxic effects Amiodarone requires special monitoring

Drug blood levels as appropriate Timeliness of dosing essential

Patient education Purpose & importance of drug Signs & symptoms of toxicity to notify MD

Digoxin (Lanoxin)

Cardiac glycoside Derived from foxglove

Properties Increases contractility Positive inotrope

Used for heart failure treatment Decreases heart rate Negative chronotrope Used to control heart rate in atrial fibrillation

Digoxin (Lanoxin)

Adverse effects usually related to toxicity Causes of toxicity Improper dosing

Hypokalemia, hypomagnesemia Signs & symptoms Anorexia, nausea, diarrhea, weakness, fatigue Bradycardia, AV block, arrhythmias

Visual changes: halos, double vision, color perception changes Monitoring for toxicity Blood levels: 0.5-2 mcg/mL normal

Check pulse before administration Digibind used to treat toxicity

Digoxin

Nursing implications Check pulse before administration Monitor electrolyte levels (K 4.0-5.2)

Cardiac monitoring with digitalization Digoxin 0.25-0.5 mg po q8 hrs x 3

Digoxin 0.125-0.25 mg IV q 4-8 hrs x 2-3 Many drug interactions

Narrow therapeutic margin Patient education Proper dosing & pulse check Blood level monitoring Drug interactions: check before starting new drugs

Other inotropes

Phosphodiesterase inhibitors Amrinone Milrinone Adrenergic agonist

Dobutamine

agonist Dopamine & agonist

Phosphodiesterase inhibitors

Amrinone (Inocor), Milrinone (Primacor) Inhibits phosphodiesterase type III intracellular levels of C-AMP intracellular calcium levels contractility

Phosphodiesterase inhibitors Use

Management of decompensated CHF Administration: IV ICU/CCU: inpatient

CHF clinics: outpatient Adverse effects Arrhythmias Thrombocytopenia Hypersensitivity Hypotension Hypokalemia

Phosphodiesterase inhibitors Use

Management of decompensated CHF Administration: IV ICU/CCU: inpatient

CHF clinics: outpatient Adverse effects Arrhythmias Thrombocytopenia Hypersensitivity Hypotension Hypokalemia

Phosphodiesterase inhibitors Nursing implications Correct potassium prior to administration to reduce incidence of

arrhythmias Cardiac & vital sign monitoring with administration

Monitor for therapeutic effect fatigue, stamina Monitor labs: K, electrolytes, platelets Nursing implications Correct potassium prior to administration to reduce incidence of

arrhythmias Cardiac & vital sign monitoring with administration

Monitor for therapeutic effect fatigue, stamina Monitor labs: K, electrolytes, platelets

Adrenergic agonists

Dobutamine (Dobutrex) Beta-1 adrenergic agonist

Stimulates sympathetic nervous system Increases contractility Used to treat

decompensated CHF

Dobutamine Dobutamine

• Adverse effects Nervousness, nausea, headache, SOB• Heart rate & BP increase Toxic effects Arrhythmias (PVC’s) Tachycardia Hypertension• Angina Nursing implications Same as phosphodiesterase inhibitors

Dopamine

Effects differ depending on dose dose Low dose: 1-2 mcg/kg/min Renal dopaminergic receptors stimulated

renal perfusion

Used to promote diuresis in CHF, renal insufficiency Moderate dose: 2-10 mcg/kg/min Beta-1 receptor stimulation

contractility & HR cardiac output High dose: 10-20 or more Alpha receptor stimulation systemic vascular resistance BP Used to support BP in cardiogenic shock, codes

Dopamine

Adverse effects Reduced renal & mesenteric perfusion with > 20

mcg/kg/min May compromise peripheral circulation at high

doses Headache, arrhythmias, hypotension,

extravasation

Nursing implications

Vital signs Cardiac monitoring I & O, daily weights Monitor renal function Assess peripheral perfusion at higher doses

Epinephrine

Pure Beta-agonist Stimulates sympathetic nervous system

Uses: increase heart rate, in emergency situations

VT, VF, asystole given every 5 minutes

Atropine

Anticholinergic increases heart rate by blocking parasympathetic

nervous system symptomatic bradycardia & high grade AV blocks asystole

Case Discussion

Mr. M is a 73 year old male admitted through the ER, being driven in by his wife. His symptoms on presentation were: 9/10 substernal chest discomfort for 2 hours, radiating to the left arm. He is also reporting nausea, difficulty breathing, and appears diaphoretic.

What do you suspect may be the cause of his symptoms?

What would your next actions be?

Case Discussion

Mr. M’s vital signs are: BP 90/50 Pulse 96 Respirations 30

O2 sat 88% on room air He is placed on O2 3L NP which brings his sat

up to 93% With the administration of O2 he also notes that

the chest discomfort is now 7/10

Case discussion

A 12 lead ECG is obtained within 5 minutes of

arrival which shows ST elevation in the anterior

leads What does this mean?

His cardiac monitor is showing the following

rhythm:

What is this rhythm?

What actions would the nurse take based on

this rhythm?

Case Discussion

The patient is prepared to be transported for an emergent primary angioplasty. As the nurse is accompanying him to the elevator, she notices this on the monitor:

What rhythm is this?What would your next actions be?

Case discussion

The patient is unresponsive, not breathing and

pulseless. The nurse calls for help and

prepares to defibrillate. After 3 successive

shocks the monitor shows:

The code team has arrived. The patient is

receiving CPR and is being bagged. The

doctor running the code orders Epinephrine

1 mg IV

What will this medication do for this patient?

Case discussion

The patient is shocked again unsuccessfully, and the doctor orders Lidocaine 75 mg IV

What will this medication do for this patient?

Case discussion

After shocking the patient again at 360 J,

the monitor shows the following rhythm:

What will you anticipate the doctor to order

for this patient?

Case discussion

The patient is brought to the cardiac cath lab

and the LAD is found to be totally occluded

The LAD is opened with angioplasty, and the

patient is then taken to ICU. The patient is

stable over the next 24 hours, then he

develops the following rhythm:

Case discussion

Case discussion

What is the heart rate and rhythm?

What would the next appropriate nursing

interventions be?

Case discussion

The nurse finds that he is feeling lightheaded, with a BP of 86/40.

What does this mean? What would be the next appropriate

nursing action?

Case discussion

The ICU standing orders include an

order for atropine 1 mg prn bradycardia.

Why is atropine effective in treating this problem?

After administration of atropine, the heart rate is up to 70, the BP is 104/70 and the patient is feeling better.

Case discussion

2 days after his MI, Mr. M has an ECHO done to evaluate his heart function. His EF is 25%.

What medications do you expect would be ordered for him post-MI?

Case discussion

On the third day, Mr. M has taken a turn for the worse. His creatinine has risen from an admission value of 1.1 to 3.0 today.

What does this mean? What might the doctor order to treat this

problem?

Case discussion

His other medications include: ASA EC 325 mg QD Enalapril 5 mg bid Atenolol 25 mg po qd

Amiodarone 200 mg qd Why do you think he is on the

amiodarone? What do you need to watch out for with

this drug?

Case discussion

Despite these efforts, he is still feeling very fatigued, and his renal function has only improved mildly to 2.5. The doctor orders a Dobutamine drip at 2 mcg/kg/min.

What effect would you expect the dobutamine to have?

Case discussion

After 4 days on the dobutamine and dopamine drips, they are tapered off, and digoxin is started.

What effect should the digoxin have on Mr M’s cardiac status?

Case Discussion

After 10 days in the hospital, Mr M is

finally preparing for discharge. He is

ambulating slowly in the hall, and his

cardiovascular status is stable. His

discharge meds include:

Case discussion

Enalapril 10 mg BID ASA EC 325 qd Digoxin 0.25 mg po qd Amiodarone 200 mg po qd Atenolol 25 mg po qd Lasix 40 mg po qd Potassium Chloride 20 meq po qd

Nitroglycerin prn What teaching points would you need to include with these

medications? What interventions might facilitate compliance with this

complex medication regimen?

Summary

In caring for the critically ill client, the nurse must anticipate the care needs and apply her knowledge and skill based on the established protocols of the agency in which he/she is employed.

Case discussion

Despite these efforts, he is still feeling very fatigued, and his renal function has only improved mildly to 2.5. The doctor orders a Dobutamine drip at 2 mcg/kg/min.

What effect would you expect the dobutamine to have?